Incoming links: Natural number
The set of all algebraic numbers forms a field.
This field contains all of the rational numbers, but it is a quadratically closed field.
Like the rationals, this field also has the same cardinality as the natural numbers, because we can specify and enumerate each of its members by a fixed number of integers from the polynomial equation that defines them. So it is a bit like the rationals, but we use potentially arbitrary numbers of integers to specify each number (polynomial coefficients + index of which root we are talking about) instead of just always two as for the rationals.
Each algebraic number also has a degree associated to it, i.e. the degree of the polynomial used to define it.
The "greatest common divisor" of two integers and , denoted is the largest natural number that divides both of the integers.
For example, is 4, because:
- 4 divides both 8 and 12
- and this is not the case for any number larger than 4. E.g.:and so on.
- 5 divides neither one
- 6 divides 12
- 7 divides neither
- 8 divides only 8